1. Field of the Invention
The present invention relates to the equipment for resistance welding of rolled sections and specifically to an apparatus for removing flash from resistance butt-weld joints in rails.
2. Description of the Prior Art
One of the ways of improving an apparatus for removing flash in resistance butt-weld joints in rails is simplification of its design, reduction of the metal and power consumption. This, however, involves the hazard that the apparatus may partially lose some of the useful features, particularly the possibility of flash removal without an allowance for a subsequent machining.
There is known in the art an apparatus for removing flash from resistance butt-weld joints in rails, comprising three cutters mounted on a carriage and embracing the rail section along the entire perimeter (see U.S. Pat. No. 3,451,309, Class 90-24). Each cutter is provided with an individual actuator for setting it to the operative position. This makes it possible to remove flash in the zone of joints from all the rail surfaces, including the underside of the rail foot, with essentially no remainder left.
The provision of individual actuators, however, makes the apparatus more bulky and complicated in construction, which in particular prevents it from being directly incorporated into a machine for resistance butt welding of rails, with the result that cutting off flash is carried out after the metal has cooled down and thus calls for a higher strength of the cutters and an increased capacity of the actuator.
Known in the art is also an apparatus for removing flash from resistance butt-weld joints in rails, comprising a base split along the axis of symmetry of the rail and made in the form of a claw clamp with two grips to engage the rail, a clamping cylinder mounted on the base substantially on the axis of symmetry thereof and kinematically linked with the grips, and cutters mounted so that, with the claw clamp closed, the cutting edges of the cutters form an outline embracing the cross-sectional perimeter of the rail, the shape of the cutting edge of the upper cutter conforming to that of the top portion of the rail head, and the shape of the cutting edges of the two side cutters, either of which is hinged to the respective grip, conforming to that of the side surfaces and rail (see U.S. Pat. No. 3,978,746, Class 83-1). The upper cutter of said apparatus is made up of two halves fixedly attached to the base, and the top portions of the side cutters are hingedly interconnected by a tie piece.
This apparatus is simpler in construction as compared to the apparatus discosed in U.S. Pat. No. 3,451,309, since the cutters are set to the operative position by a single actuator. Moreover, the apparatus disclosed in U.S. Pat. No. 3,978,746 can be incorporated, as a component, into a claw-type machine for resistance butt welding of rails, which will enable flash to be cut off by a much lower effort because this is effected immediately after welding, when the metal is not cooled down yet.
The apparatus allows flash to be cut off with an allowance for a subsequent machining over the entire cross-sectional perimeter of the rail. In the subsequent machining of the entire contact surface including the head and web of the rail the remainder of flash is cut off together with the metal layer being removed. The rail foot underside bearing against sleepers requires essentially no further machining. In laying the rails, however, cases are possible when the rail butt joints are located on the sleepers. The contact between the surfaces of the rail and the sleeper in such places is effected over a small area of the projecting portion of the flash of the rail foot not cut off, which is intolerable under the railroad operating conditions.
In this case, after flash has been removed from the rail foot with the use of the above-described apparatus, an additional grinding of rails is required at the butt joint by a stone, which entails major inconveniences and extra expenses under the field conditions.